Evidence for pressure-induced node-pair annihilation in Cd3As2

TL;DR

This study demonstrates that applying high pressure to Cd3As2 causes a shift in Dirac nodes and a topological phase transition, revealed through magnetotransport and X-ray diffraction, highlighting pressure as a tool to control topological properties.

Contribution

It provides experimental evidence of pressure-induced topological phase transition in Cd3As2 via node-pair annihilation and Fermi surface evolution, supported by first-principles calculations.

Findings

Berry phase change at 1.3 GPa

Fermi surface shrinkage below 2.5 GPa

Axial compression shifts Dirac nodes toward the Brillouin zone center

Abstract

As an intermediate state in the topological phase diagram, Dirac semimetals are of particular interest as a platform for studying topological phase transitions under external modulations. Despite a growing theoretical interest in this topic, it remains a substantial challenge to experimentally tune the system across topological phase transitions. Here, we investigate the Fermi surface evolution of Cd3As2 under high pressure through magnetotransport. A sudden change in Berry phase occurs at 1.3 GPa along with the unanticipated shrinkage of the Fermi surface, which occurs well below the structure transition point (~2.5 GPa). High pressure X-ray diffraction also reveals an anisotropic compression of the Cd3As2 lattice around a similar pressure. Corroborated by the first-principles calculations we show that an axial compression will shift the Dirac nodes towards the Brillouin zone center and eventually introduces a finite energy gap. The ability to tune the node position, a vital parameter of Dirac semimetals, can have dramatic impacts on the corresponding topological properties such as the Fermi arc surface states and the chiral anomaly. Our study demonstrates axial compression as an efficient approach for manipulating the band topology and exploring the critical phenomena near the topological phase transition in Cd3As2.